9. Sex

This probably comes as no surprise to many people, but sex is highly correlated with being happy. Two UK economists, David Blanchflower and Andrew Oswald, conducted a statistical study on the relationship between people’s happiness and their sexual activities in the U.S. They found that people who have sex on a regular basis (i.e., four or more times a week) fall within the happiest group of Americans. Men also enjoy sex slightly more than women, and sex brings more happiness to the highly educated than to the less educated. Overall, their results suggest that sex makes people happy. Either that or happier people just have more sex. They are likely both perfectly valid statements.